As the light diminishes daily and temperatures drop deciduous trees and shrubs are triggered into action to cope with winter. They know that with low light levels, shorter exposure to light and the possibility of freezing soils preventing their roots functioning properly it is going to be increasingly difficult to produce food using the green chlorophyll in their leaves to harness sunlight and carbon dioxide to manufacture it. Therefore, they get rid of the green chlorophyll pigment because it is no longer useful. As a result, other pigments in the leaves such as carotenoids and anthocyanins begin to show demonstrating colours in varying shades of yellow, orange, red and brown before they fall off the tree.
The leaves of the Bramble (Rubus fructicosus) or Dris in Irish are worth examining closely. It produces a wide spectrum of colours in its autumn leaves ranging from deep red to vibrant yellows (1a:1b;1c).
The different species of Maple (Acer spp.) or Mailp in Irish also exhibit vibrant and eye-catching colours now (2a; 2b).
The leaves of Guelder rose (Viburnum opulus) or Caor chon in Irish turn to orange and red with clusters of deep red berries hanging from its boughs to complement the overall loveliness of its leaves (3).
The leaves of the Sessile Oak (Quercus petraea) or Dair ghaelach in Irish and those of the English oak (Quercus robur) or Dair ghallda in Irish change from yellow to brown (4).
The leaves of Beech (Fagus sylvatica) or Feá in Irish change to a reddish-brown colour (5).
Black blotches from the tar spot fungus appear on the leaves of the Sycamore (Acer pseudoplatanus) before they turn brown and fall off. This fungus does no harm to the trees (6).
Finally, two non-native climbers display the most stunning displays of all autumn colour. The Boston ivy (Parthenocissus tricuspidate) with its three-lobed leaves and Virginia creeper ((Parthenocissus quinquefolia) with its five lobed leaves are in full brilliance in their red and purple coats now (7a: 7b).